Safety device for time fuzes



Feb. 17, 1970 J. MULLER SAFETY DEVICE FOR TIME FUZES 3 Sheets-Sheet 1 Filed Oct. 1'7, 1967 z zymvron. "(7%; e f Mu 2 Qei- WW i Feb. 17, 1970 J. MULLER 3,495,533

SAFETY DEVICE FOR TIME: FUZES Filed Oct. 17, 1967 3 Sheets-Sheet 5 IN VEN TOR.

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United States US. Cl. 10278 1 Claim ABSTRACT OF THE DISCLOSURE A time fuze for a projectile having a safety device including an inertia weight mounted around a cylindrical member which carries a striker pin stem movable therein and a second inertia weight is associated with the first inertia weight so that together they increase the safety factor for the fuze.

The invention relates to a further development of the time safety device for a time and percussion fuze for projectiles with low acceleration, with and without twist, especially for rocket projectiles according to Patent No. 3,124,074. In that case, a cylindrical body, provided at its periphery with a helical groove on the pin bolt, can be driven through an inertia weight provided with a cross bolt meshing with the helical groove, which is guided nonrotatably in the fuze housing and carries a safety finger parallel to the axis, which secures the balance-speed regulator of the time mechanism.

With the present further development of this time fuze, an increase of safety, both during transport as well as after firing, is striven for. Fuzes according to the type pertinent here, as well as the fuze according to Patent No. 3,124,074, are customarily secured during transport by means of a safety pin. It can happen that, after the pin has already been drawn, the projectile will still be transported once more or further. If in that case, it will drop hard onto the shell base, the fuze which, according to supposition, is intended for projectiles with low acceleration and, therefore, for fuzes that can start easily, may become armed. It is the object of the present invention to prevent this latter. This is solved in that a second inertia weight, movable in the same direction as the first, will be connected in series with the first inertia weight and in that a disconnectable lock has been arranged at the end of the path of its return travel, which lock will block the first inertia weight in its rest position. If now the projectile is accidentally dropped hard onto its shell base, then the parallel inertia impulse will merely cause a retreating of the second inertia weight, held in its starting position by feed springs, whereby, however, it will not reach the end of its return path and therefore is unable to release the lock which blocks or holds the first inertia weight in its rest position. Therefore, the falling impulse has passed away before the actual inertia drive for the time fuze could become operable. In the further development of the fuze according to Patent No. 3,124,074 and according to the invention, it is not only the safety factor during transport but also safety with regard to time which will be fulfilled since the action times of the two inertia weights connected in series are added up together.

In the case of a preferred design of the invention, the second inertia weight has been developed as a ring movable with regard to the feed springs and encompassing the first weight, having the same center. For practical purposes, it is inserted into a cylindrical bore of the central member of the fuze, and in its rest position, it partially encompasses the likewise cylindrical body of the drive atent mechanism built up on supporting columns above the base of the fuze. For blocking the first inertia weight, double levers, which can swing out radially on the base of the drive mechanism, will be arranged advantageously, which has on one arm a bend which is directed forward with an abutting surface cooperating with the inside edge of the lower front surface of the second inertia weight and which has on the other arm a supporting plate running perpendicular in relation to the axis of the fuze, which in a blocking position are located below the supporting fingers which project from the rear front surface of the first inertia weight and which release bores in the base of the fuze in their releasing position into which the supporting fingers submerge.

Further objects will be apparent from the following description when considered in connection with the accompanying drawings in which:

FIGURE 1 is a longitudinal section of a portion of the projectile taken on line .A-B of FIG. 2 in the direction of the arrows and showing the safety mechanism in the safety position,

FIGURE 2 is a cross section taken on line A-B of FIG. 1 in the direction of the arrows,

FIGURE 3 is a longitudinal section of a portion of the projectile of FIGS. 1 and 2 taken on line C-D of FIG. 4 in the direction of the arrows and taken in a position of the projectile turned approximately relative to FIG. 1 and showing the safety mechanism still in safety position,

FIGURE 4 is a cross section taken on line C-D of FIG. 3 in the direction of the arrows,

FIGURE 5 is a cross section similar to FIG. 1 with the parts in the same position but completely at nonsafety position and taken on line E-F of FIG. 6 in the direction of the arrows,

FIGURE 6 is a cross section taken on line E-F of FIG. 5 in the direction of the arrows, and

FIGURE 7 is a section of a detail taken on line G-H of FIG. 6 in the direction of the arrows.

The striker pin stem 15b is shown with the same reference character in US. Patent No. 3,124,074 and the cylindrical member 107 is mounted thereon. This latter has a spiral groove 107a in its periphery in which a lateral pin 108 projects which is secured in an intertia weight 109. This latter is axially slidable on the mechanism carrier posts and 106 and therefore is guided in a non-rotary manner and they carry in axial parallel relationship the safety finger 114 to provide a sure means to connect with the balance wheel regulator of the time mechanism.

Upon firing during the acceleration of the projectile, the intertia weight 109 will slide to the rear and since it is positively guided on the posts 105 and 106, its lateral pin 108 by its projection in the spiral groove 107a will induce a rotation of the member 107, which by means of the delay mechanism 110, 111, 112 and 113 will be braked. The return movement of the inertia weight 109 will operate against the supporting spring 119.

The time safety mechanism is so adjusted that at the end of the definite time safety period of the inertia weight 109 with its back surface, the intermediate plate 102 has been reached. In his position the balance regulator will be freed by the forward end of the safety finger 114.

To this mechanism from the US. Patent No. 3,124,074 there is now added the second inertia weight 209. This latter is in the form of a surrounding cylinder around the inertia weight 109 and urged and movable by spring 210 in the chamber 211a of the fuze portion 211. In its safety position it encloses partly the likewise cylindrical mechanism L on the supporting posts 105 and 106 over the fuze socket.

A pin bolt channel in the blocking plate 117 is on the fuze bottom plate 212 similar to US. Patent No. 3,124,- 074 and having a plate group 102, 103 and 104 mounted around the post 213 having a swing lever 214, 214a and 214b mounted thereon which may swing radially outwardly. On its arms 214a, FIGURES 3, 6 and 7, these lever arms 214a are directed forwardly with head portions 214a which are for the purpose of operating together with the inner edge 209a of the lower head surface of the inertia weight 209 in such a way that upon the return movement of the intertia weight 209, FIG- URES 3, 5 and 7, the intertia weight 209 will swing over the forward end slanting surfaces 214 of the double lever 214 around its rotation pin 213, FIGURE 6, in clockwise direction. By this swing movement the supporting plates 214b which will be on the ends of the lever arms 214]) out of the range of the support fingers 215 which will spring out from the back of the end surface or face of the first intertia weight 109 and will rest in the non-operative position, FIGURE 1, on the support plates 214b Thereby the blocking of the first inertia weight 109 will be accomplished and this can now operate under the continuing back pressure acceleration of its above described back movement by the drive of the spiral member 107 and thus the brake mechanism will operate where-by the support finger 215 will enter the bore 216 in the fuze base.

I claim:

1. Time-safety device for a time and percussion double fuze for projectiles with low acceleration, with and without twist, especially for rocket porjectiles comprising a fuze housing, a drive mechanism, a cylindrical body provided on its periphery with a helical groove, a pin bolt on which the body is rotatably mounted, an inertia weight connected to drive the body on the pin bolt, a cross bolt in the weight meshing with the helical groove, a timing mechanism having a balance regulator means to provide non-rotational linear movement of the inertia weight in the fuze housing, a second intertia weight mounted in the fuze housing and which is movable in the same direction as the first-mentioned inertia weight and connected in series with the first-mentioned inertia weight, a disconnectable lock for the first-mentioned inertia weight so that at the end of its return path the disconnectable lock Will block the first-mentioned inertia weight in its rearward position, a safety finger engaging the balance regulator and mounted on the first-mentioned inertia weight parallel to a longitudinal axis of the fuze to secure the balance regulator of the timing mechanism, and radially swinga'ble double arm levers located on the bottom of a recess provided by said drive mechanism and having on one lever arm a bent portion directed forward with an abutting surface cooperating with the inside edge at the lower front surface of the secondmentioned inertia weight and on the other arm a supporting plate running perpendicularly in relation to the axis of the fuze which lever arms when in blocking position are located below supporting fingers provided on, and which project from, the rear front surface of the first-mentioned inertia weight and which lever arms release in their releasing position toward openings provided in the base of the fuze and into which the supporting fingers may submerge.

References Cited UNITED STATES PATENTS 3,124,074 3/1964 Kaiser et al. 10278 3,375,786 4/1968 Marchiaro 10278 FOREIGN PATENTS 1,250,350 11/1960 France.

BENJAMIN A. BORCI-IELT, Primary Examiner T. H. WEBB, Assistant Examiner US. Cl. X.R. 10280, 83, 84 

